First records for Culex (Melanoconion) limacifer Komp and Culex (Melanoconion) dunni dyar from Guatemala.

Larvae of Culex (Melanoconion) limacifer Komp and Culex (Melanoconion) dunni Dyar were collected during June 2004 in Guatemala. All specimens were individually reared to the adult stage. Specimens were identified based upon examination of the male genitalia and characters of the associated larval and pupal exuviae. These are the first records of these 2 species in Guatemala.

Variation in vector competence for dengue 2 virus among 24 collections of Aedes aegypti from Mexico and the United States.

Aedes aegypti from 24 collections in Mexico and the United States were challenged orally with dengue 2 virus JAM1409 (DEN-2 JAM1409). The vector competence (VC) of the populations ranged from 24% to 83%. Mosquito populations from the Yucatan exhibited greater VC than those from other areas of Mexico. The presence or absence of a midgut infection barrier (MIB) and a midgut escape barrier (MEB) was determined for mosquitoes in each population. The percentage of mosquitoes exhibiting an MIB ranged from 14% to 59%, and those exhibiting an MEB ranged from 4% to 43% in the collections. The MIB and MEB were not completely independent as determined by regression analysis. Midgut infection rates were dose dependent.

Flavivirus susceptibility in Aedes aegypti.

Aedes aegypti is the primary vector of yellow fever (YF) and dengue fever (DF) flaviviruses worldwide. In this review we focus on past and present research on genetic components and environmental factors in Aedes aegypti that appear to control flavivirus transmission. We review genetic relationships among Ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. We describe current research into how genetic and environmental factors jointly affect distribution of vector competence in natural populations. Based on this information, we propose a population genetic model for vector competence and discuss our recent progress in testing this model. We end with a discussion of approaches being taken to identify the genes that may control flavivirus susceptibility in Ae. aegypti.